<!DOCTYPE html>
<style>
#a, #c {
    width:25px;
    height:50px;
    background: blue;
}
</style>
<p>There should be a blue <em>square</em> below.</p>
<div>
    <div id="a"></div><div id="b"></div><div id="c"></div>
</div>
<script>
    document.body.offsetTop;
    document.getElementById('a').style.display = 'inline-block';
    document.getElementById('b').style.position = 'absolute';
    document.getElementById('c').style.display = 'inline-block';
</script>
